Android GNSS in Nutshell
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The document discusses how Android provides location services using GNSS, the advantages of using the Galileo system, and various applications of this technology. It highlights the integration of Android's APIs for enhanced positioning accuracy and discusses tools available for developers. The presentation emphasizes the potential for new applications and market opportunities in GNSS positioning with smartphones.
Android GNSS in Nutshell
- 1. Android and GNSS pseudoranges in the nutshell Galileo Hackathon webinar Dr. Lukasz Bonenberg 28th April 2017 1
- 2. The road ahead 1 How does Android provide position? 2 Why Galileo? 3 So what? 4 Summary 2
- 3. How does Android provide position?
- 5. But how do I know my location? developer.android.com/guide/topics/location/strategies. html ©Google 5
- 7. Looking under the hood ©Google 7
- 9. Why Galileo?
- 10. Android GNSS observations • Pseudorange/Pseudorange Rate (code) • HW clock • Navigation data • Accumulated Delta Range (Carrier) • additional information (Doppler, observation uncertainty, SNR ect) Observations provided by android.location are chipsets dependent1. 1Qualcomm Snapdragon 650 or 820, Broadcom BCM4774 or Intel WCS2x00 10
- 11. Navigation Concept Figure courtesy of Prof T Moore 11
- 14. GNSS accuracy Figure courtesy of Prof T Moore 14
- 16. So what?
- 17. Position app anybody? A number of positioning applications exist • Geo Tracker bit.ly/A_GT • GPS Status bit.ly/A_GS • SV Viewer bit.ly/SV_Trimble Those use android.gms.location and Sensor from android.hardware. What could we do with android.location? 17
- 18. Sample workflow • calculate Pseudorange; • get corrections via NTRIP (DGPS); • estimate position; • provide position to Google Play Services. • Convert observables to RINEX; • Expand NMEA logger for additional messages 18
- 20. More phones than ppl William Starkey/CC0 20
- 21. Applications? • GIS and asset management • Crowdsorcing • Low cost CORS network • Space weather • sensor fusion • improving position in urban areas (Shadow Matching) But what could I do with my phone with cm-dm level accuracy? 21
- 22. Sample workflow • calculate Pseudorange; • get corrections via NTRIP (DGPS); • estimate position; • provide position to android.gms.location. • Convert observables to RINEX; • Expand NMEA logger for additional messages; • Send timing and synchronisation information; 22
- 23. Sample code • Existing apps using external hardware: • uCentre bit.ly/uCentre • NTRIP bit.ly/2q701V3 • RTKGPS+ bit.ly/RTKplus • Google code github.com/google/gps-measurement-tools • my fork - github.com/DfAC/gps-measurement-tools • calculating pseudoranges - github.com/DfAC/AndroidGNSS • RTKGPS github.com/tomojitakasu/RTKLIB 23
- 24. Summary
- 25. What we covered today 1 How does Android provide position? 2 Why Galileo? 3 So what? 4 Summary 25
- 26. Take away • android.gms.location abstracts and simplifies position use within application. Main focus is battery use. • There is existing android.hardware API giving us access to the phone sensors. • Android 7 adds GNSS observations API - android.location, providing more GNSS positioning options (external corrections, longer observation times, more sophisticated algorithms ect) at the cost of battery power; • Relevant GNSS open source tools exist. • This allow us to experiment with new ideas and new mass market opportunities and applications. 26
- 27. Useful links • GSA market report - bit.ly/2h5qhP0 • GSA user report bit.ly/2i36aRj • Shadow matching • Simon Banville blog - www.blackdotgnss.com/2016/09/20/ ppp-with-smartphones-are-we-there-yet/ • Rokybun blog - http://rokubun.cat/2016/06/30/ android-n-preview-gnss-measurements/ • my edits to Google code - github.com/DfAC/gps-measurement-tools • calculating pseudoranges - github.com/DfAC/AndroidGNSS • T. Humphrey et al (2016) On the Feasibility of cm-Accurate Positioning via a Smartphone’s Antenna and GNSS Chip 27
- 28. Thank you Questions? Lukasz.Bonenberg@nottingham.ac.uk My presentations can be found at www.slideshare.net/LukaszKosmaBonenberg 28